As is widely known, automobiles, such as a gasoline engine car, a hybrid car, and an electric motorcar, have accumulator battery means (lead accumulator battery, lithium ion battery, capacitor, etc.). The above-mentioned automobiles use electric power stored in the accumulator battery means in traveling and generally perform charging as well.
For example, in the case of the gasoline engine car, the electric power of the accumulator battery means is used as operation energy, such as of ignition and an engine ECU, while electric power is stored in the accumulator battery means by rotating a generator with the use of rotational energy of the engine.
Moreover, in the case of the hybrid car and the electric car, the electric power stored in the accumulator battery means is used to rotate the motor to gain the driving power, while regeneration energy obtainable at the time of deceleration or when traveling in a downhill is converted to electric power, which is stored in the accumulator battery means.
Since such rotational energy of the engine and regeneration energy at the time of deceleration are largely affected by a traveling situation, a timing at which the electric power can be stored in the accumulator battery means and the quantity of accumulated energy are also affected by the traveling situation largely. Therefore, it is very important to make the accumulator battery means store electric power efficiently according to the traveling situation. Then, as a technique of making the accumulator battery means store electric power efficiently, there is proposed an invention described in Patent Document 1 described below.
Usually, with the purpose of preventing degradation of the accumulator battery means, the remaining quantity of accumulated energy is controlled to be near the center between an upper limit and a lower limit. For example, the upper value is set to a charging rate of 60% and the lower limit is set to a charging rate of 40%, and the remaining quantity of accumulated energy is controlled to a charging rate of around 50%. A drive control apparatus described in Patent Document 1 is configured to pursue efficiency of accumulation of electricity by temporarily enlarging this control width (a width between the upper limit and the lower limit) when conditions are fulfilled, e.g., when a route includes a downhill section that enables large regeneration energy to be recollected.                Patent Document 1: JP-2005-160269 A        
However, in order to temporarily enlarge the control width in this way, when it is not grasped whether there is a downhill section on the route that enables large energy to regenerate, sufficient charging efficiency cannot be obtained (because the battery needs to be discharged sufficiently before the vehicle reaches the downhill section). Therefore, a drive control device described in Patent Document 1 is configured to grasp a predicted travel route by searching a route from the current position to a destination based on information inputted through a user interface. In Patent Document 1, although setting of the destination by the driver is considered as a basic procedure, the destination does not need to be set by the driver but may be predicted from past driving patterns of the driver. However, in this case, even when the prediction of the destination is proper, generally multiple routes reaching the destination can be considered, and therefore the driver does not necessarily choose a predicted route. Therefore, the accuracy of prediction of the route that the driver actually chooses may be not sufficient. When the prediction of the route that the driver actually chooses is wrong, a sufficient quantity of accumulated energy is no longer obtainable. In a worst case, the vehicle may get into inability of traveling.